Mold



Oct. 5, 1937. B. s. SAMPLE ET Ax. l 2,094,823

MOLD

' Filed June 27. 1955 lNyENToRS A, @Zw

Patented Oct. 5, 1937 UNITE `STATES PATEsir essie MOLD Waffe ApplicationJune 27, 1935, Serial No. 28,680

4 Claims.

This invention relates to a method and apparatus for suspending aninsert in a mold cavity.

In cases where expediency or necessity requires that an article withinserts be formed in a mold cavity in which an insert is suspended,various methods of suspension have been heretofore resorted to, all ofwhich are more Vor less unsatisfactory. One of the most widely practicedmethods of suspension relies on frictional retention of the suspended.insert in a mold cavity and is accomplished by merely iitting a portionof the insert tightly into a corresponding opening in a cavity wall.This method requires the exertion of a considerable human force upon ausually small Vinsert in the more or lessV restricted space between opencompanion molds, and more often than not is theifrictionally engaging,often-times plated surface of the insert marred. Another known methodofy suspension creates an artificial bond between the'insert and thereceiving opening in a'cavitywall, for instance by applying someresinous varnish tothe holding portion of the insert prior to itsdeposition in the receiving opening, whereupon the varnish coat forms abond `between the insert and the engaging wall of the opening afterdeposition of the insert in the comparatively hot mold. This lattermethod is not only costly for several reasons but also too slow topermit expedient molding since the insert has to be held in thereceiving opening for some time before the varnish coat forms asufficiently strong bond to hold the insert in place.

It ispan object of the present invention to suspend fanv insert ina'mold cavity by a partial .va'cuum, thereby 'to overcome thediiiiculties of the heretofore practiced methods of suspension.

It is anotherV object of the present invention to clear the insertreceiving opening in a cavity wall of possible ash' by a blast ofcompressed air.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing wherein a preferred embodiment of the present invention isclearly shown.

In the drawing:

i Fig. 1 is a diagrammatic illustration of an apparatus for employing apartial vacuum to suspend an insert in each cavity of a closed mold.

Fig. 2 is a modiiicationr ofthe apparatus shown inFig. Il'and includesan insert holding plate, permitting the simultaneous introduction of aplurality'v of inserts into their respective openings in certain cavitywalls.

Eig. V3 isfa'diagrammatic view of an insert holding plate which may beusedA with the apparatus of Fig. 2. 1

Referring t0 Fig. 1, the reference numerals lil and i2 designatecooperating molds, either one of which may be reciprocable relative tothe other. In the present instance mold iii is preferably stationarywhereas mold i2 is movable relative thereto for opening or closing themolds. Reference numeral i4 designates a number of cavities in mold l2which may be of any suitable shape to define the shape of an articleformed in the molds. For simplicitys sake no cavities are shown in moldit, the flat surface iii o-f said mold `merely forming flat walls Vit ofthe cavities ii in mold I2, but for all intents and purposes mold i@ maycomprise cavities of any suitable shape to complete those of mold i2 indefining the shape of an article formed in these molds. Mold iii isprovided with a plurality of comparatively small openings 20 whichterminate at the cavity wall forming portions i8 of rnold i@ and areofthe same cross-sectional size and shape as the Shanks 22 of inserts 2iwhich are to be suspended in the mold cavities. To explain one ofvarious reasons whylinserts have to be frequently suspended in a moldcavity, inserts 25 are shown supported on the cavity Walls 2l. Each oneor" the openings 2t is in communication with a conduit 2t by means of anelbow or other suitable connector 28. The conduits 26 are in turncommunicating with a division chamber 3i? which is formed by anysuitable casing or housing 32. Chamber iii communicates with anyconventional three-Way valve 3d through a conduit 36. Communicating withthis threeway valve 34 through a conduit te is any suitable vacuumproducing means such as a vacuum pump (not shown). Also communicatingwith valve 34 through a conduit #iii is a supply of compressed air whichis suitably replenished, for instance by a compressor (not shown). Valve34 is manually selectively shiftable into any one of three positions ofwhich the inoperative position is shown in Fig. l. This valve may beshifted from inoperative position either to provide communicationbetween conduits liti and Sii or between conduits 38 and 3d, throughintermediation of a duct i2 in said valve Sli. Mold i2 may be moved awayfrom the closed position in Fig. 1 and into closed position again in anysuitable manner Whatever. While the molds lil, i2 are separated, theoperatorof the mold shifts valve 34 into the position into which duct i2thereof provides communication between conduits 38 and 36. The operatorthen inserts the Shanks 22 of the inserts 24 into the mold openings'ltwherein they as well as the area of communication between the' vacuumpump and these openings 20 are comparatively small, the inserts 24 maybe successivelyT introduced into their respective mold openings sincethere is a sufficient vacuum created in each opening 20 to hold thefirst insert in place even though the remaining openings 25 are as yetin frere communication with the atmosphere. Success 'of this procedureis further enhanced. by. crowding the vacuum producing means, the valvei34 and the cavities of a mold into the smallestV l possible space and bylocating the distributing chamber 3i)V substantially centrally of thecavities. The only restriction upon the number of insert receivingopenings 20 which are connected to the distributing chamber 30 is placedby the drawing force of the partial vacuum in each opening 2Q which hasto hold an insert in place even when the remaining openings 2i] have notyetreceivedV their insert.

After all inserts have been thus placed in the mold, moldable material,for instance bakelite, is placed into the cavities I4, and mold l2 isthereafter moved into closed position thereby compressing the charge inthe cavitiesV into the articles 45. The molds Ill, l2 'are properlyheated Vso that the molded articles may become vulcanized. Uponseparation of the molds, the operator shifts valve 34 into the positionin which the compressed air conduit 4E! communicates with conduit 35through valve duct 42, resulting in discharge ofV a blast of compressedair through each one of Vthe moldopenings 25 to remove such flash ofmolded maj terial which may have penetrated into the slight clearancebetween the insert Shanks 22 and the mold openings 25. The cavities i4of the movable mold are so designed that the molded articles remaintherein during separation of the molds and are thereafter removed fromlthe cavi-ties in any suitable manner. In case the operator shouldaccidentally omit the insertion of one or more inserts into the molds,it is obvious that the empty.V

openings 2E! willV then be clogged up with molded material. To removesuch material, the connectors V28 are provided with detachable plugs 29,permitting access to the openings 20 with a suitable tool to punch outthe material which clogs VVup these openings.

Wherever an exclusive conduit connectsone insert receiving opening withavacuum pump, theY cross-sectional area of such opening is limited onlyby the weight of Vthe insert which is to be held in said opening by thedrawing force of the partial vacuum therein. However, where one vacuumpumpY is connected to several insert receiving openings of approximatelythe size of those in Fig.

successive deposition of the inserts is impossibleY since too muchairenters those openings which are as yet without aninsert and thusweaken the partialvacuum in all openings to such an extent that noinsert will be held in place. Nevertheless,

in order successfully to use one vacuum'pump in I conjunction with apluralityof insert receiving openings 52 of considerable cross-section,all the inserts Ell are simultaneously introduced into their respectiveopenings 52, in which case a suicient partial vacuum is simultaneouslycreated in all of these openings after a comparatively short period ofholding these inserts in their openings. In order simultaneously tointroduce and thereafter hold the inserts 54 for a short period in theopenings 52, these inserts are placed in suitable recesses 56 of a.plate 58 which is provided with a suitable handle portion Slifermanipulating said plate. The insert receiving recesses 56 of plate 53have tapered side walls 62 to reduce the frictional engagement of theinserts with the recesses 5B to a minimum so that upon removal of theplate axially of the inserts 54 and after theirV vacuum retention in theopenings 52, the recesses 56 have no tendency to remove these insertsfrom their openings. The recesses 56 of plate 58 of course locate theinserts 54 in the same relation to eachother as they will assume upondeposition in'their respective openings 52. In Fig. 2 only thedistributingfchamber 64 is shown, but it is to beV Vthe molds 50, 66.The three-way valve which is Y omitted in Fig. 2 but which may beprovided in the same manner as shown inFig. 1, may naturally be shiftedto provide communication between a compressed air supply and the moldopenings 52 It is likewise to be understood that alto blow outrsuchparticles of molded material which happenrto penetrate to these openingsduring a preceding molding operation. 'v Y In order properly to guideplate 58 such that the t insert Shanks properly enter their respectiveopenings 52, plate 58 is preferably provided witha plurality oflocatingpins 10 which are adapted to register with suitable holes (notshown) in mold 55 prior to the entry of the insert Shanks into theopenings 52.

VWhereas throughout the description reference was had to a mold forproducing articles of moldable material suchas bakelite, it is to beunderstood that metal could be cast into these molds without prejudiceto the explained vacuum suspension ofHinserts. In that case it is ofcourse imperative that the casting metal has a lower melting temperaturethan the insert and the mold material. Y Y

AWhilethe embodiment of the present invention las herein disclosed,constitutes aV preferred form,

t ing leading to a lower wall of the mold cavity and receiving the shankof an insert the head f of which projects into the cavity and the shankand opening being of congruent cross-section, the head to be embedded inthe molded article and the shankto depend therefrom; and a device forproducing in said opening a partial vacuum which acts on the exposedshank end, thereby holding the insert suspended. Y Y Y 2. The.combination of a mold having openings leading to a lower wall of themold cavity and each receiving the shank of .an insert the head of whichprojects into the cavity, the shanks and openings being of congruentcross-section and the heads to be embedded in the molded article and theShanks to depend therefrom; a vacuum producing device; conduitsproviding communication between the device and all openings which are ofcomparatively small area wherefore a sufcient partial vacuum is createdin any opening immediately upon insertion of a shank therein to hold theinsert suspended even though other openings have not yet received ashank.

3. The combination of a mold having an opening leading to a lower wallof the mold cavity and receiving the shank of an insert the head ofwhich projects into the cavity and the shank and opening being ofcongruent cross-section, the head to be embedded in the molded articleand the shank to depend therefrom; a vacuum producing device; mechanismfor supplying compressed gas; and control means operable to provide orintercept communication between opening and device or mechanism,respectively, the partial vacuum in the opening acting on the exposedshank end to hold the insert suspended and the compressed gas beingadapted to blow possible ash from the opening.

4. The combination of a mold having openings leading to a lower wall ofthe mold cavity and each receiving the shank of an insert the head ofwhich projects into the cavity, the shanks and openings being ofcongruent cross-section and the heads to be embedded in the moldedarticle and the shanks to depend therefrom; a vacuum producing device;mechanism for supplying compressed gas; and control means operablesimultaneously to provide or intercept communication between allopenings and the device or mechanism, respectively, the partial vacuumin the openings being adapted to act on the exposed shank ends andholding the inserts suspended and the compressed gas being adapted toblow possible ash from all openings.

BASIL S. SAMPLE. WILLIAM A. FLETCHER..

